Glass and method of making



Patente'cl lax- 0,1931

mx METILJQF Pligtts'BURe'g}. PENNSYLVANIA; T v i ".iL' EWY BKJN Y--: i

" .eness -afinivnamnoboii ii takiifeij The present invention relates 0 glass goni: positionsp and morerparticularly toi 'aglass having a relatively lOW coefficient of expan sioni'and a relatively" high tensile strength,

and inethod of making'samef lF- I a r v 1 Sinceglas's is 'a'relatiyely poor conductor ofheat, changes in temperatureiat one point'i do not. materially :aflect the temperatures of peratufe are rapidr 'and" where lithe coeffioient T 1 lA-ttempts have b-enaadea redudihemfl eifi cient of expansion by increasing the silica f r content of the. glass. -iThis .;requires a {ma- 5' ther such an; increase of ilicaiimust he'tr'nade by reduction 'of' the percentage of? other: constituents which g oc casions zfdifiiculties' in manufacture, thereby mendering this method 've'ryobjection'able; s til-Ar; V Attempts have al so'ibeenizrhade to reduce the coefficient of expansiion byzchang ing the constituents of the} glass but no :change' fpro f posed-so far has given satisfactory results without increasing the cost of; theglass to' a point Where-it-cannot'be-Iused:commercially.

Thezprese'nt invention-eliminates.the 'cultiesi enumerated above-and: is the 'refsultaof .c the di'scovery of exceptional results attained; bye alveryii'nexpensive elementwhich notionly reduces the: coefficient of expansion flout also; increases the tensileistrength nd quality 0 fthe glass' without introducing; other :conip so small that it does not liiaterially disturb-z adjoining portions. The local expansion o c- .casioned} ,-no1i -unifoi mhea ting produces internal stresses which, due to the hard brit tle nature of glass, cause:breakage;2' This? is particularly true' WhereYthe changes'in 'ter'n ot'exp'ansion is1 relativ'e'ly'hig hfiiOther being' equal, the "higher the coefiicient of ex;

pansion,the; greater the tentlency of theglass' togcra'ck orbreak, un'defr rapid changes in; temperature. The reason for this is that the? "local: expansion tends'tojf'elongate thewadjag' 'Qentportions'. r1.

terial increaseinzthe operatingaternperatui e of-the glass furnace which is difficult mobtaiIi-With present fuel and equipment. Fure cationsl'i Furth'r-i 1 the; quantity f required the usual proportions ofthe basic ingredients.-

' Anobject ofthe invention is lto'reducefv the coeflicient of expansion; of 'co'ni ne'rcial glassj' :2 ear-em amans?' i 7 f idem. I

"sufficiently substantia l'lg j "ageclue to local changesingtemperature.

addition of an'inexpensivei-elernentsuch? as;

crease [the "tensile s'trength of :glass tvit on 3 materially increasingjits cost-. {g ",VA further -object;,{o'f the-"iinvention better theiquality.ofglass byihe Lad tio'ninvention inipra-Cti;

ass

an djthe ten'sile str ngth u eieo eliminate break- Another object 'ofxithe iny'ent-i'onis theme-g" v cluction of the fcoefiicient'ofexpansionloy the-' ber fllium-or-its equivalent to the cOHStituentSS ofthe g lilss. z- Another object .QfftlTQJIIVGDtiOIYiSA o in, 1 c a v v 'rn l "'g s by" h T additionof anfin'expensivelement such i beryllium comp C1? t0l3h6100fi$t creasethe coefli'cientgoii:expansionancl o in slnalliqu ntitie s- 'ofa beryllium compoundthe i constituent thereo'fl in "their .11

Otherantlfurther olqectsoi theinuentions I iou'sfupon an;flunderstanding of Y the illustra', i e embodiment {about'fto be de scribed; jand?manyafadyantages the than? i; those greferred 'ftqherein; will occur 'fto ione: skilled in the artuponemployment of t While"'the ingrelientsflgncl iprop H thereof". in :grla's rnay be -valued;{over Wid i r "simple" illustrative glass: the ,j

purposes of this description "may (CaO)(The composition mayiconta-i n' other 7 elements in sm'allfquai'itities' for the purpose 3 off coloring anclthe like; :[The co'eflicient -Of "expansion ofa glass of thisl clfara'cteriisabout 7 X 107 I The glasschosen,and {theiingrgdi em; and. proportions thereof are merely il 1 zlustrative and areanot intended to l'imit} the l present invention, which 'is 'app'licableg also other formsofglassiy havejjdisco fered that by; he arlditionao small uen' esbfs e ptheriab' ry i mf o'fiexpansion may )he tierially-fincreased-"*An addition 0 V as one per cent ofberylliumjwill reclucejth eflicint of expansion by half and the ad' tion oif a higher percentage of beryllium will reduce the coeflicient of expansion to such an obtain andfusesat'high temperatures.

taining about 66% of silica, about of. aluminumand about14-% beryllium, will fuse 7 fit rather. than ahindrance.

extent that it is negligible and a non-break able glassjis formed in so far as changesin temperature are concerned.

Beryllium inits pure state is diflicult to ever, beryllium in its commercialstate conat ordinary glass furnace temperatures, andcan be obtained at a relatively, low cost without difliculty. Since silica is one of the'con clent commercialberyllium; added thereto to prod-1.10s one percentvof beryllium inthe contents would'be about 944 pounds of s'and,-380 pounds of soda,-10O pounds offlime' "aridlOO pounds 0f commercial beryllium, The; 66

1 pounds of silica in thelOQ pounds-of commercial berylliumraise the silica content to L000 poundsnoted above, "The'QOf poundsof-aluminnan in the 100 pounds :of commercial, beryle' I lium brin the equivalent lime, content ,to 120 pounds.-

beryllium mixturegive about one per cent of'beryllium. "ltqwill'be; understoodof course,

that the amounts noted areapproximate only, and that; changes inith'e proportions of? the Y contents within, the wide range of commercialvariations, will not afiect the inven+ The addition of beryllium inithe quantities noted does; not materially increase or change the; required conditions in the glass furnace.

V Further,.beryllium as mined com-mercially is relatively inexpensive and does'not materially increase the: cost of glass; Onhtheother hand the use of the beryllium"greatly increases the ability of the glass to withstand" rapid changes in temperature and also greatlye increases the quality and tensile strength thereof.- 'Experimentsshow that as much as .pansion as an increase of4%inthe.silica con- Y of beryllium "will Y gives proportionately e greater increase in the quality of: the-glass and a proportionately greater decreaseiin Y the coeflicient of expansion,-without introduc-. j

a. V one-half of one per rcentofi'beryllium is-equal':

.v as

lywefiective. in increasing the quality of the glass and in decreasing; the coefiicient' of extent anda greater increase in the percentage I ing' the complications occasionedby increase of-theisilica content. a It --wi ll seen; that :a: high. quality; glass How - dent of expansion 'comprisi-n-gusual constitu e14 pounds oiberylliujm'. in the aberyllium'compound.

with a low coeflicient of expansion and a high tensile strength has been provided at a low cost. The glass may be manufactured withr present apparatus and without necessitating changes in temperatures of the glass furnaces. 'The method employed issimple and eflective, and readily applicable under existing conditions in glass manufacturing plants.

variouschangescair be made in the proportions of the ingredients enumerated above and as various equivalents'may be substituted for those named without departing from the spirit of thepresentinvention, it isdesired; that the above descriptionxbe understood as illustrative and not in a, limiting Y sense;

, Having thus describedamy invention, 1

claim': Y I s I -1. Aglasshaving a, relatively low coeflients of soda, lime, silicaa-glass with :a small a percentage of a beryllium compound therein;

, A; glass containing silica, lime, soda, and a-berylliumcompoun V Y Y ;A,gl;1ss formed from; silica, lime, soda, alumina' andlessthan five per cent of a beryllium compound.

4.;Agl-ass containing silica,,lime,=and soda e in suitable proportions for commercial. glass with a; berylliumv compound therein to reduce thecoeflicient of expansion ofthe glass.

1 5.7 A composition, comprising-silica, lime, and soda in suitable proportions and less than 5% ofqa' beryllium compound therein a tOdecrease the ,coeflicient' of expansion and;

to increase the tensile strength thereofi -6 Aglas'scomprising about.74%c silica, 16% lime, about-9%. soda and: about 1% of 7. A composition Lfor forming glass com- I prising: about 74% silica, about 16% V lime, i abouti 9% 'soda; and: a. small percentage of a *beryllium compound added thereto J to decrease: the coeflicient off-expansion thereof.

. 8. The method ofimaking soda, lime, silica glass, which comprisesadding a .qu antity of a beryllium compound not exceeding 5% to'an then fusing'the mixture Y Y I 9;- As an article of manufacture, glass contaming; silica, lime, soda, alumina .and .a

beryllium compound. I w

l "10- Aglass resulting from the fusion beaf fbatehcomprising soda, lime, silica and a Y quantity-ofbuyllium compound,.not exceed-' ingzfiveipe'r cent. a V Y Y 11; A glass havinga low coeflicient'of expansion resulting from the fusion of a batch co u prising soda, lime, silica, and'ra vquantity ofgal berylliumcompound.

, unfused batch of'glass making materials,;and 

